I've been using a tooth paste with hydroxypatite for a little more than one year. Mostly for the enamel in my front teeth. I can see it works to some extend. The corrosion from the upper side of the teeth have stopped and I can see improvement of the already eroded side but I am talking about less than a milimiter. It is not a quick solution, and it requires dental higyne routinely. As for the price, I found that of you get the tooth paste in bulk it is more affordable.